The invention relates to a device for generating electrical energy in a rotating system for the purpose of supplying electric current to electronic components in the system, comprising external forces, acting on the system, that act on piezoelectrically active energy converters in the system, as a result of which electrical energy is generated, and comprising an electronic system for processing the generated electrical energy and transferring it to the components.
Such a device is known from DE 603 10 104 T2. In that case, a piezoelectric element, an actuation mass provided for contact with the piezoelectric element, and a control circuit that is electrically connected to the piezoelectric element are arranged inside a tyre or pneumatic tyre. The actuation mass is provided to displace the piezoelectric element as a result of the external forces that act on the actuation mass during use, in order to generate an electrical charge. This electrical charge, or energy, is made available to the components by the control circuit.
It is disadvantageous in this case that the piezoelectric element and the actuation mass are heavy, and affect the rotating system or tyre in its rotational characteristics. Moreover, this device usually cannot provide sufficient energy to supply, for example, sensors and transmission elements in a lasting and reliable manner, with reliable functioning over a long service life, even under extreme acceleration conditions of some 10,000 g.
In addition to capacitive and inductive systems for energy transmission, and batteries or accumulators for energy storage, piezoceramic-based systems are also known, which, depending on their design—for example, realized as mass oscillators—are relatively sensitive to the forces and deformations that occur during operation in a tyre, as a rotating system, and that can result in the components rapidly being destroyed.
Also known are solutions that are integrated into an inner layer of the tyre running surface and that, owing to their mass, greatly impair the running smoothness, or produce relatively large imbalances.